The effects of syntactic and lexical complexity on the comprehension ...

<strong>The</strong> Effects <strong>of</strong> Syntactic <strong>and</strong> Lexical / Arya, Hiebert & Pearsonmore likely, more complex ideas. In other words, conceptual <strong>complexity</strong> could be drivingdifficulty, <strong>and</strong> the number <strong>of</strong> words in a sentence simply indexes (rather than causes) that<strong>complexity</strong>. In psychological terms, the longer the sentence, the greater the likelihood thatmultiple discrete ideas, called propositions, are embedded in it (Kintsch, 1998). Examples 1-3illustrate this point.1. Tree frogs have red eyes.2. Tree frogs have red eyes that help them see <strong>and</strong> find food.3. Tree frogs have red eyes that help them see <strong>and</strong> find food at night.Example 1 conveys two complete ideas or propositions: (a) tree frogs have eyes, <strong>and</strong> (b)these eyes are red. Example 2 has two additional propositions: these red eyes help the frogto (a) see food <strong>and</strong> (b) to find food. Example 3 actually adds three more propositions, oneexplicit <strong>and</strong> two implicit. <strong>The</strong> explicit proposition is that the frogs do the seeing <strong>and</strong> findingat night. That proposition invokes two more entailments: that (a) that frogs are awake atnight <strong>and</strong> (b) that their eyes help them to see in the dark. <strong>The</strong> amount <strong>and</strong> explicitness <strong>of</strong> theinformation provided in each sentence increases as the number <strong>of</strong> embedded structures(e.g., adjectives, relative clauses, <strong>and</strong> prepositional phrases) increases. Readers must be ableto unpack the propositions within complex sentences <strong>and</strong> establish their logical relations toone another to underst<strong>and</strong> all <strong>of</strong> the information presented.Any account <strong>of</strong> text difficulty that uses sentence length to establish the readability <strong>of</strong>texts assumes, at least implicitly, that unpacking the propositions within a complex sentenceis more difficult than making connections across related propositions stated in simplesentences. A short sentence in itself may be easier to comprehend than a complex one.However, the challenge may come when the reader needs to construct a cohesion model <strong>of</strong>meaning from a series <strong>of</strong> short sentences. To illustrate this distinction, a complex sentencesuch as the third example above can be broken up into five simple sentences, as in Example4:4. Tree frogs have eyes. <strong>The</strong>se eyes are red. <strong>The</strong>se eyes help them see. <strong>The</strong>y help themfind food. <strong>The</strong> tree frogs are awake at night.Just as the complex sentence required readers to unpack propositions within the sentence,having to connect ideas across discrete, simple sentences may place other task dem<strong>and</strong>s onreaders. Connective cues (e.g., conjunctives, conjunctive adverbs, <strong>and</strong> relative clauses) <strong>and</strong>other embedded structures serve as markers to guide readers to a full underst<strong>and</strong>ing <strong>of</strong> theideas presented. Eliminating these connective cues may increase the inference burden onreaders (Bowey, 1986; Pearson & Camperell, 1981); relationships, such as cause-effect orproblem-solution, or sequence, that were explicitly cued in the more complex versions haveto be inferred in the less complex versions. Ozuru, Dempsy, Sayroo <strong>and</strong> McNamara (2005)found that adding cohesive devices such as connectives that made relationships betweensentences more explicit were beneficial for students reading science texts about unfamiliartopics. Students were able to correctly answer more questions when texts had <strong>syntactic</strong>structures that made meaning more explicit than when texts were less cohesive. Similarly,Rawson (2004) found that texts that presented more ambiguous <strong>syntactic</strong> structures withunmarked, reduced relative clauses (the girls told about the movie were excited) were moredifficult for college students (all <strong>of</strong> whom had high reading abilities) than texts with moreexplicit structures, containing marked clauses (the girls who were told about the movie wereexcited).While some <strong>complexity</strong> in sentences can support readers in comprehending text,presumably there is a point where sentences can become too complex for novice or109